Recruitment or activation of mast cells in the liver aggravates the accumulation of fibrosis in carbon tetrachloride-induced liver injury.

Liver diseases caused by viral infections, alcoholism, drugs, or chemical poisons are a significant health problem: Liver diseases are a leading contributor to mortality, with approximately 2 million deaths per year worldwide. Liver fibrosis, as a common liver disease characterized by excessive collagen deposition, is associated with high morbidity and mortality, and there is no effective treatment. Numerous studies have shown that the accumulation of mast cells (MCs) in the liver is closely associated with liver injury caused by a variety of factors. This study investigated the relationship between MCs and carbon tetrachloride (CCl4)-induced liver fibrosis in rats and the effects of the MC stabilizers sodium cromoglycate (SGC) and ketotifen (KET) on CCl4-induced liver fibrosis. The results showed that MCs were recruited or activated during CCl4-induced liver fibrosis. Coadministration of SCG or KET alleviated the liver fibrosis by decreasing SCF/c-kit expression, inhibiting the TGF-ß1/Smad2/3 pathway, depressing the HIF-1a/VEGF pathway, activating Nrf2/HO-1 pathway, and increasing the hepatic levels of GSH, GSH-Px, and GR, thereby reducing hepatic oxidative stress. Collectively, recruitment or activation of MCs is linked to liver fibrosis and the stabilization of MCs may provide a new approach to the prevention of liver fibrosis.

Chimeric antigen receptor-modified macrophages ameliorate liver fibrosis in preclinical models.

BACKGROUND & AIMS: Treatments directly targeting fibrosis remain limited. Given the unique intrinsic features of macrophages and their capacity to engraft in the liver, we genetically engineered bone marrow-derived macrophages with a chimeric antigen receptor (CAR) to direct their phagocytic activity against hepatic stellate cells (HSCs) in multiple mouse models. This study aimed to demonstrate the therapeutic efficacy of CAR macrophages (CAR-Ms) in mouse models of fibrosis and cirrhosis and to elucidate the underlying mechanisms. METHODS: uPAR expression was studied in patients with fibrosis/cirrhosis and in murine models of liver fibrosis, including mice treated with carbon tetrachloride, a 5-diethoxycarbonyl-1, 4-dihydrocollidine diet, or a high-fat/cholesterol/fructose diet. The safety and efficacy of CAR-Ms were evaluated in vitro and in vivo. RESULTS: Adoptive transfer of CAR-Ms resulted in a significant reduction in liver fibrosis and the restoration of function in murine models of liver fibrosis. CAR-Ms modulated the hepatic immune microenvironment to recruit and modify the activation of endogenous immune cells to drive fibrosis regression. These CAR-Ms were able to recruit and present antigens to T cells and mount specific antifibrotic T-cell responses to reduce fibroblasts and liver fibrosis in mice. CONCLUSION: Collectively, our findings demonstrate the potential of using macrophages as a platform for CAR technology to provide an effective treatment option for liver fibrosis. CAR-Ms might be developed for treatment of patients with liver fibrosis. IMPACT AND IMPLICATIONS: Liver fibrosis is an incurable condition that afflicts millions of people globally. Despite the clear clinical need, therapies for liver fibrosis are limited. Our findings provide the first preclinical evidence that chimeric antigen receptor (CAR)-macrophages (CAR-Ms) targeting uPAR can attenuate liver fibrosis and cirrhosis. We show that macrophages expressing this uPAR CAR exert a direct antifibrotic effect and elicit a specific T-cell response that augments the immune response against liver fibrosis. These findings demonstrate the potential of using CAR-Ms as an effective cell-based therapy for the treatment of liver fibrosis.

[Ascites CD100 levels and immunomodulation effects in the peripheral blood of patients with liver cirrhosis combined with spontaneous bacterial peritonitis].

Objective: To observe the level and detection of ascites CD100 on the activity of CD4(+) and CD8(+) T lymphocytes in vitro in the peripheral blood of patients with liver cirrhosis combined with spontaneous bacterial peritonitis. Methods: Peripheral blood and ascites were collected from 77 cases of liver cirrhosis (49 patients with liver cirrhosis combined with simple ascites and 28 patients with liver cirrhosis combined with SBP), and peripheral blood was collected from 22 controls. Soluble CD100 (sCD100) in peripheral blood and ascites was detected by an enzyme-linked immunosorbent assay. Flow cytometry was used to detect membrane-bound CD100 (mCD100) on the surface of CD4(+) and CD8(+)T lymphocytes. CD4(+) and CD8(+)T lymphocytes in ascites were sorted. CD4(+)T lymphocyte proliferation, key transcription factor mRNA, and secreted cytokine changes, as well as CD8(+)T lymphocyte proliferation, important toxic molecule mRNA, and secreted cytokine changes, were detected after CD100 stimulation. The killing activity of CD8(+)T cells was detected by direct contact and indirect contact culture systems. Data conforming to normality were compared using one-way ANOVA, a student's t-test, or a paired t-test. Data that did not conform to a normal distribution were compared using either the Krusal-Willis test or the Mann-Whitney test. Results: There was no statistically significant difference in plasma sCD100 level between patients with liver cirrhosis combined simple ascites (1 415 ± 434.1) pg/ml, patients with liver cirrhosis combined with SBP (1 465 ± 386.8) pg/ml, and controls (1 355 ± 428.0) pg/ml (P = 0.655). The ascites sCD100 level was lower in patients with liver cirrhosis combined with SBP than that of patients with simple ascites [(2 409 ± 743.0) pg/ml vs. (2825±664.2) pg/ml, P=0.014]. There was no statistically significant difference in the level of mCD100 in peripheral blood CD4(+) and CD8(+) T lymphocytes among the three groups (P > 0.05). The levels of mCD100 in ascites CD4(+) and CD8(+) T lymphocytes were higher in patients with liver cirrhosis combined with SBP than those in patients with simple ascites (P < 0.05). CD100 stimulation had no significant effect on the proliferation of CD4(+) and CD8(+)T lymphocytes in the ascites of patients with liver cirrhosis combined with SBP (P > 0.05). There were no significant effects on the expression of transcription factors in effector CD4(+)T lymphocytes (T-bet, retinoic acid associated solitary nuclear receptor γt, aromatic hydrocarbon receptor) or secretion of cytokines (interferon-γ, 17, and 22) (P > 0.05). CD100 stimulation had increased the relative expression of perforin, granzyme B, and granlysin mRNA and the levels of secreted interferon-γ and tumor necrosis factor-α, killing activity in ascites CD8+ T lymphocytes of patients with liver cirrhosis combined with SBP (P < 0.05). Conclusion: The active form of CD100 is sCD100 instead of mCD100. There is an imbalance between the expression of sCD100 and mCD100 in the ascites of patients with cirrhosis combined with SBP. sCD100 can enhance the function of CD8(+)T lymphocytes in the ascites of patients with cirrhosis combined with SBP and thus is one of the potential therapeutic targets.

Cell-specific Deletion of NLRP3 Inflammasome Identifies Myeloid Cells as Key Drivers of Liver Inflammation and Fibrosis in Murine Steatohepatitis.

BACKGROUND & AIMS: Nonalcoholic fatty liver disease (NAFLD) is the leading cause of chronic liver disease worldwide. The NLRP3 inflammasome, a platform for caspase-1 activation and release of interleukin 1ß, is increasingly recognized in the induction of inflammation and liver fibrosis during NAFLD. However, the cell-specific contribution of NLRP3 inflammasome activation in NAFLD remains unknown. METHODS: To investigate the role of NLRP3 inflammasome activation in hepatocytes, hepatic stellate cells (HSCs) and myeloid cells, a conditional Nlrp3 knock-out mouse was generated and bred to cell-specific Cre mice. Both acute and chronic liver injury models were used: lipopolysaccharide/adenosine-triphosphate to induce in vivo NLRP3 activation, choline-deficient, L-amino acid-defined high-fat diet, and Western-type diet to induce fibrotic nonalcoholic steatohepatitis (NASH). In vitro co-culture studies were performed to dissect the crosstalk between myeloid cells and HSCs. RESULTS: Myeloid-specific deletion of Nlrp3 blunted the systemic and hepatic increase in interleukin 1ß induced by lipopolysaccharide/adenosine-triphosphate injection. In the choline-deficient, L-amino acid-defined high-fat diet model of fibrotic NASH, myeloid-specific Nlrp3 knock-out but not hepatocyte- or HSC-specific knock-out mice showed significant reduction in inflammation independent of steatosis development. Moreover, myeloid-specific Nlrp3 knock-out mice showed ameliorated liver fibrosis and decreased HSC activation. These results were validated in the Western-type diet model. In vitro co-cultured studies with human cell lines demonstrated that HSC can be activated by inflammasome stimulation in monocytes, and this effect was significantly reduced if NLRP3 was downregulated in monocytes. CONCLUSIONS: The study provides new insights in the cell-specific role of NLRP3 in liver inflammation and fibrosis. NLRP3 inflammasome activation in myeloid cells was identified as crucial for the progression of NAFLD to fibrotic NASH. These results may have implications for the development of cell-specific strategies for modulation of NLRP3 activation for treatment of fibrotic NASH.

Cancer Risk in Patients With Autoimmune Hepatitis: A Nationwide Population-Based Cohort Study With Histopathology.

We aimed to determine the risk of incident cancer in autoimmune hepatitis (AIH) compared with the general population and siblings. AIH was defined by the presence of a medical diagnosis of AIH and results of examination of a liver biopsy specimen in a nationwide Swedish population-based cohort study. We identified 5,268 adults with AIH diagnosed during 1969-2016 and 22,996 matched, general population, reference individuals and 4,170 sibling comparators. Using Cox regression, hazard ratios were determined for any incident cancer, and subtypes were determined from the Swedish Cancer Register. During follow-up, a cancer diagnosis was made in 1,119 individuals with AIH (17.2 per 1,000 person-years) and 4,450 reference individuals (12.0 per 1,000 person-years). This corresponded to a hazard ratio of 1.53 (95% confidence interval: 1.42, 1.66). Cancer risk was highest in those with cirrhosis. There was a 29.18-fold increased risk of hepatocellular carcinoma (HCC) (95% confidence interval: 17.52, 48.61). The annual incidence risk of HCC in individuals with AIH who had cirrhosis was 1.1% per year. AIH was also linked to nonmelanoma skin cancer (hazard ratio (HR) = 2.69) and lymphoma (HR = 1.89). Sibling analyses yielded similar risk estimates for any cancer (HR = 1.84) and HCC (HR = 23.10). AIH is associated with an increased risk of any cancer, in particular, HCC and extrahepatic malignancies. The highest risk for cancer, especially HCC, is in patients with cirrhosis.

Recovery from Liver Failure and Fibrosis in a Rat Portacaval Anastomosis Model after Neurointermediate Pituitary Lobectomy.

Liver diseases, including cirrhosis, viral hepatitis, and hepatocellular carcinoma, account for approximately two million annual deaths worldwide. They place a huge burden on the global healthcare systems, compelling researchers to find effective treatment for liver fibrosis-cirrhosis. Portacaval anastomosis (PCA) is a model of liver damage and fibrosis. Arginine vasopressin (AVP) has been implicated as a proinflammatory-profibrotic hormone. In rats, neurointermediate pituitary lobectomy (NIL) induces a permanent drop (80%) in AVP serum levels. We hypothesized that AVP deficiency (NIL-induced) may decrease liver damage and fibrosis in a rat PCA model. Male Wistar rats were divided into intact control (IC), NIL, PCA, and PCA+NIL groups. Liver function tests, liver gene relative expressions (IL-1, IL-10, TGF-ß, COLL-I, MMP-9, and MMP-13), and histopathological assessments were performed. In comparison with those in the IC and PCA groups, bilirubin, protein serum, and liver glycogen levels were restored in the PCA+NIL group. NIL in the PCA animals also decreased the gene expression levels of IL-1 and COLL-I, while increasing those of IL-10, TGF-ß, and MMP-13. Histopathology of this group also showed significantly decreased signs of liver damage with lower extent of collagen deposition and fibrosis. Low AVP serum levels were not enough to fully activate the AVP receptors resulting in the decreased activation of cell signaling pathways associated with proinflammatory-profibrotic responses, while activating cell molecular signaling pathways associated with an anti-inflammatory-fibrotic state. Thus, partial reversion of liver damage and fibrosis was observed. The study supports the crucial role of AVP in the inflammatory-fibrotic processes and maintenance of immune competence. The success of the AVP deficiency strategy suggests that blocking AVP receptors may be therapeutically useful to treat inflammatory-fibrotic liver diseases.

Serum Fractalkine Levels Were Positively Associated with Disease Severity of Liver Cirrhosis.

OBJECTIVE: The chemokine receptor CX3CR1 and its specific ligand fractalkine (CX3CL1, FKN) has been implicated in modulating inflammatory and fibroproliferative diseases. The current study was performed to investigate the correlation of serum fractalkine levels with disease severity of liver fibrosis/cirrhosis (LC). METHODS: 162 LC patients and 140 healthy controls well enrolled in our study. Serum fractalkine levels were detected using commercial ELISA kit. Liver biopsy specimens were obtained using 16 G disposable needle in LC patients. The Child-Pugh grade was recorded to assess liver function. ROC curve analysis was performed to assess the potential diagnostic power of serum fractalkine with regard to the disease severity of Child-Pugh grade system. Pathological assessment of cirrhotic severity was performed by Laennec staging system. The L3 skeletal muscle index (L3SMI) was applicated to assess the nutrition status. RESULTS: Serum fractalkine levels were significantly higher in LC patients compared with healthy controls. The case group included 50 Child-Pugh A patients, 59 Child-Pugh B patients, and 53 Child-Pugh C patients. Cirrhosis patients with Child-Pugh C had drastically higher serum fractalkine levels compared with those with Child-Pugh B and A. Child-Pugh B patients showed significantly higher serum PACAP concentrations compared with those with Child-Pugh A. ROC curve analysis demonstrated that serum fractalkine may act as a potential indicator for disease progression of LC determined by Child-Pugh classification. Besides, serum fractalkine levels were positively related to ALT and AST concentrations and negatively related to L3SMI. CONCLUSION: Serum fractalkine levels were positively associated with disease severity of LC.

ß2-Adrenergic Receptor Enhances the Alternatively Activated Macrophages and Promotes Biliary Injuries Caused by Helminth Infection.

The autonomic nervous system has been studied for its involvement in the control of macrophages; however, the mechanisms underlying the interaction between the adrenergic receptors and alternatively activated macrophages (M2) remain obscure. Using FVB wild-type and beta 2 adrenergic receptors knockout, we found that ß2-AR deficiency alleviates hepatobiliary damage in mice infected with C. sinensis. Moreover, ß2-AR-deficient mice decrease the activation and infiltration of M2 macrophages and decrease the production of type 2 cytokines, which are associated with a significant decrease in liver fibrosis in infected mice. Our in vitro results on bone marrow-derived macrophages revealed that macrophages from Adrb2-/- mice significantly decrease M2 markers and the phosphorylation of ERK/mTORC1 induced by IL-4 compared to that observed in M2 macrophages from Adrb2+/+ . This study provides a better understanding of the mechanisms by which the ß2-AR enhances type 2 immune response through the ERK/mTORC1 signaling pathway in macrophages and their role in liver fibrosis.

Liver fibrosis promotes immunity escape but limits the size of liver tumor in a rat orthotopic transplantation model.

Liver fibrosis plays a crucial role in promoting tumor immune escape and tumor aggressiveness for liver cancer. However, an interesting phenomenon is that the tumor size of liver cancer patients with liver fibrosis is smaller than that of patients without liver fibrosis. In this study, 16 SD rats were used to establish orthotopic liver tumor transplantation models with Walker-256 cell lines, respectively on the fibrotic liver (n = 8, LF group) and normal liver (n = 8, control group). MRI (magnetic resonance imaging) was used to monitor the size of the tumors. All rats were executed at the third week after modeling, and the immunohistochemical staining was used to reflect the changes in the tumor microenvironment. The results showed that, compared to the control group, the PD-L1 (programmed cell death protein receptor-L1) expression was higher, and the neutrophil infiltration increased while the effector (CD8+) T cell infiltration decreased in the LF group. Additionally, the expression of MMP-9 (matrix metalloproteinase-9) of tumor tissue in the LF group increased. Three weeks after modeling, the size of tumors in the LF group was significantly smaller than that in the control group (382.47 ± 195.06 mm3 vs. 1736.21 ± 657.25 mm3, P < 0.001). Taken together, we concluded that liver fibrosis facilitated tumor immunity escape but limited the expansion of tumor size.

Emerging Roles of T Cells in the Pathogenesis of Nonalcoholic Steatohepatitis and Hepatocellular Carcinoma.

Nonalcoholic fatty liver disease (NAFLD) has become the most common chronic liver disease worldwide. A significant proportion of patients with NAFLD develop a progressive inflammatory condition termed nonalcoholic steatohepatitis (NASH), which may eventually advance to cirrhosis and hepatocellular carcinoma (HCC). NASH is characterized by steatosis, hepatocyte ballooning, and lobular inflammation. Heightened immune cell infiltration is a hallmark of NASH, yet the mechanisms whereby hepatic inflammation occurs in NASH and how it contributes to disease initiation and progression remain incompletely understood. Emerging evidence indicates that intrahepatic T cell immune mechanisms play an integral role in the pathogenesis of NASH and its transition to HCC. In this review, we summarize the current knowledge regarding the T cell-mediated mechanisms of inflammation in NASH. We highlight recent preclinical and human studies implicating various subsets of conventional and innate-like T cells in the onset and progression of NASH and HCC. Finally, we discuss the potential therapeutic strategies targeting T cell-mediated responses for the treatment of NASH.

NLRC5 Deficiency Deregulates Hepatic Inflammatory Response but Does Not Aggravate Carbon Tetrachloride-Induced Liver Fibrosis.

The nucleotide-binding leucine-rich repeat-containing receptor (NLR) family protein-5 (NLRC5) controls NF-κB activation and production of inflammatory cytokines in certain cell types. NLRC5 is considered a potential regulator of hepatic fibrogenic response due to its ability to inhibit hepatic stellate activation in vitro. To test whether NLRC5 is critical to control liver fibrosis, we treated wildtype and NLRC5-deficient mice with carbon tetrachloride (CCl4) and assessed pathological changes in the liver. Serum alanine transaminase levels and histopathology examination of liver sections revealed that NLRC5 deficiency did not exacerbate CCl4-induced liver damage or inflammatory cell infiltration. Sirius red staining of collagen fibers and hydroxyproline content showed comparable levels of liver fibrosis in CCl4-treated NLRC5-deficient and control mice. Myofibroblast differentiation and induction of collagen genes were similarly increased in both groups. Strikingly, the fibrotic livers of NLRC5-deficient mice showed reduced expression of matrix metalloproteinase-3 (Mmp3) and tissue inhibitor of MMPs-1 (Timp1) but not Mmp2 or Timp2. Fibrotic livers of NLRC5-deficient mice had increased expression of TNF but similar induction of TGFß compared to wildtype mice. CCl4-treated control and NLRC5-deficient mice displayed similar upregulation of Cx3cr1, a monocyte chemoattractant receptor gene, and the Cd68 macrophage marker. However, the fibrotic livers of NLRC5-deficient mice showed increased expression of F4/80 (Adgre1), a marker of tissue-resident macrophages. NLRC5-deficient livers showed increased phosphorylation of the NF-κB subunit p65 that remained elevated following fibrosis induction. Taken together, NLRC5 deficiency deregulates hepatic inflammatory response following chemical injury but does not significantly aggravate the fibrogenic response, showing that NLRC5 is not a critical regulator of liver fibrosis pathogenesis.

Neutrophil extracellular traps in patients with liver cirrhosis and hepatocellular carcinoma.

Neutrophil extracellular traps (NETs) are web-like structures consisting of DNA, histones and granule proteins, released from neutrophils in thrombus formation, inflammation, and cancer. We asked if plasma levels of the NET markers myeloperoxidase (MPO)-DNA and citrullinated histone H3 (H3Cit)-DNA, are elevated in liver cirrhosis and hepatocellular carcinoma (HCC) and if the levels correlate with clinical parameters. MPO-DNA, H3Cit-DNA, and thrombin-antithrombin (TAT) complex, as a marker of coagulation activity, were measured using ELISA in plasma from 82 patients with HCC, 95 patients with cirrhosis and 50 healthy controls. Correlations were made to clinical parameters and laboratory data and patients were followed for a median of 22.5 months regarding thrombosis development. H3Cit-DNA was significantly (p < 0.01) elevated in plasma from cirrhosis (66.4 ng/mL) and HCC (63.8 ng/mL) patients compared to healthy controls (31.8 ng/mL). TAT levels showed similar pattern (3.1, 3.7, and 0.0 µg/mL respectively, p < 0.01). MPO-DNA was significantly (p < 0.01) elevated in cirrhosis patients (0.53 O.D.) as compared to controls (0.33 O.D.). Levels of MPO-DNA and H3Cit-DNA correlated positively with Child-Pugh and MELD score. TAT was increased in all Child-Pugh and MELD groups. In multivariable logistic regression, Child B and C liver cirrhosis were independent predictors of elevated H3Cit-DNA in plasma. Levels of MPO-DNA and H3Cit-DNA were similar in patients with or without history of thrombosis, or thrombus formation during follow-up. In conclusion, plasma markers of NET formation are elevated in liver cirrhosis and correlate to the degree of liver dysfunction in patients with liver cirrhosis and/or HCC. The presence of HCC did not further increase the plasma levels of NET markers as compared to patients with cirrhosis only.

MiR-130a-3p Alleviates Liver Fibrosis by Suppressing HSCs Activation and Skewing Macrophage to Ly6Clo Phenotype.

Emerging evidences have highlighted the crucial role of microRNAs (miRNAs) in the liver cirrhosis, but the relationship between miR-130a-3p and liver cirrhosis is not entirely clear. As we all know, schistosomiasis, as one of the zoonoses, can lead to liver cirrhosis when it advances. In this study, we investigated the biological functions of miR-130a-3p on the liver fibrosis of schistosomiasis in vivo and in vitro. The mice infected with Schistosoma japonicum (S. japonicum) were treated with lentivirus vector (LV)-miR-130a-3p by hydrodynamic injection through the tail vein. Our findings showed significantly decreased expression of miR-130a-3p both in the serum of patients with cirrhosis and in the liver of mice infected with S. japonicum. The results showed that LV-miR-130a-3p could effectively enter into the liver and alleviate liver granulomatous inflammation and collagen deposition. Simultaneously, LV-miR-130a-3p-promoted macrophages presented the Ly6Clo phenotype, concomitant with the decreased expression of the tissue inhibitor of metalloproteinases (TIMP) 1, and increased the expression of matrix metalloproteinase (MMP) 2, which contributed to the dissolution of collagen. Furthermore, overexpression of miR-130a-3p not only inhibited the activation and proliferation of hepatic stellate cells (HSCs) but also induced the apoptosis of HSCs. In addition, we also confirmed that miR-130a-3p enables to bind with mitogen-activated protein kinase (MAPK) 1 and transforming growth factor-beta receptors (TGFBR) 1 and TGFBR2 genes and inhibit the expressions of these genes. Our findings suggested that miR-130a-3p might represent as the potential candidate biomarker and therapeutic target for the prognosis identification and treatment of schistosomiasis liver fibrosis.

Are Pattern Recognition Receptors Associated with Hepatocellular Carcinoma?

BACKGROUND: Hepatocellular carcinoma (HCC) is one of the important causes of mortality due to malignancy. Toll-like receptors (TLRs) are very important in liver pathophysiology in terms of their roles in the innate immune system, such as the regulation of inflammation, wound healing, stimulation of adaptive immune responses, promotion of epithelial regeneration, and carcinogenesis. In this study, we planned to examine the role of TLR1 (rs4833095, rs5743551) and nucleotide-binding oligomerization domain (NOD2) (rs2066844, rs2066845, rs2066847) polymorphisms in the development of HCC and their effects on the clinical presentation of HCC patients. METHODS: Our study was designed prospectively. Cirrhotic and HCC patients who were followed up in our clinic between January 2015 and September 2018 were included in the study. Sex, age, cirrhosis etiology, Child-Pugh class, and MELD scores were recorded. TLR1 and NOD2 polymorphisms were studied by the PCR method. RESULTS: HCC developed in 88 (31.4%) of the 280 patients who were followed up, either during the recruitment phase of our study or during the follow-up. The mean follow-up time of our patient group was 17.04 ± 11.72 months, and the mean follow-up time of HCC patients was 12.09 ± 10.26 months. TLR1 (rs5743551) polymorphism was associated with HCC development (P = .003). TLR1 (rs5743551) and NOD2 (rs2066844) polymorphisms were associated with the development of spontaneous bacterial peritonitis (SBP) in the HCC patient group (P = .013 and P = .021, respectively). CONCLUSION: We think that increased bacterial translocation in cirrhotic patients may contribute to HCC development by causing chronic inflammation, especially in patients with TLR 1 (rs5743551) polymorphism.

ATF6 promotes liver fibrogenesis by regulating macrophage-derived interleukin-1α expression.

Macrophages contribute to liver fibrogenesis by the production of a large variety of cytokines. ATF6 is associated with the activation of macrophages. The present study aimed to investigate the role of ATF6 in the expression of macrophage-derived cytokines and liver fibrogenesis after acute liver injury. Following thioacetamide (TAA)-induced acute liver injury, the characteristics of the occurrence of liver fibrosis and the secretion of cytokines by macrophages were first described. Then, the role of various cytokines secreted by macrophages in activating hepatic stellate cells (HSCs) was tested in vitro. Finally, endoplasmic reticulum stress (ER-stress) signals in macrophages were detected following liver injury. siRNA was used to interfere with the expression of ATF6 in macrophages to verify the influence of ATF6 on cytokine expression and liver fibrogenesis after liver injury. A single intraperitoneal injection of TAA induced acute liver injury. The depletion of macrophages attenuated acute liver injury, while it inhibited liver fibrogenesis. During acute liver injury, macrophages secrete a variety of cytokines. Most of these cytokines promoted the activation of HSCs, but the effect of IL-1α was most significant. In the early stage of acute liver injury, ER-stress signals in macrophages were activated. Interference of ATF6 expression suppressed the secretion of cytokines by macrophages and attenuated liver fibrogenesis. Overall, in the early stage of acute liver injury, ATF6 signals promoted the expression of macrophage-derived cytokines to participate in liver fibrogenesis, and IL-1α exhibited the most significant role in promoting the activation of HSCs and liver fibrogenesis.

A triterpenoid-enriched extract of bitter melon leaves alleviates hepatic fibrosis by inhibiting inflammatory responses in carbon tetrachloride-treated mice.

Liver fibrosis is a progression of chronic liver disease characterized by excess deposition of fibrillary collagen. The aim of this study was to investigate the protective effect of a triterpenoid-enriched extract (TEE) from bitter melon leaves against carbon tetrachloride (CCl4)-induced hepatic fibrosis in mice. Male ICR mice received TEE (100 or 150 mg kg-1) by daily oral gavage for one week before starting CCl4 administration and throughout the entire experimental period. After intraperitoneal injection of CCl4 for nine weeks, serum and liver tissues of the mice were collected for biochemical, histopathological and molecular analyses. Our results showed that TEE supplementation reduced CCl4-induced serum aspartate aminotransferase and alanine aminotransferase activities. Histopathological examinations revealed that CCl4 administration results in hepatic fibrosis, while TEE supplementation significantly suppressed hepatic necroinflammation and collagen deposition. In addition, TEE supplementation decreased α-smooth muscle actin (α-SMA)-positive staining and protein levels of α-SMA and transforming growth factor-ß1. TEE-supplemented mice had lower mRNA expression levels of interleukin-6, tumor necrosis factor-α, and toll-like receptor 4. Moreover, TEE (150 mg kg-1) supplementation significantly reduced intrahepatic inflammatory Ly6C+ monocyte infiltration. We demonstrated that TEE could ameliorate hepatic fibrosis by regulating inflammatory cytokine secretion and α-SMA expression in the liver to reduce collagen accumulation.

Retinoic Acid: A New Old Friend of IL-17A in the Immune Pathogeny of Liver Fibrosis.

Despite all the medical advances mortality due to cirrhosis and hepatocellular carcinoma, the end stages of fibrosis, continuously increases. Recent data suggest that liver fibrosis is guided by type 3 inflammation with IL-17A at the top of the line. The storage of vitamin A and its active metabolites, as well as genetics, can influence the development and progression of liver fibrosis and inflammation. Retinoic acid (active metabolite of vitamin A) is able to regulate the differentiation of IL-17A+/IL-22-producing cells as well as the expression of profibrotic markers. IL-17A and its pro-fibrotic role in the liver is the most studied, while the interaction and communication between IL-17A, IL-22, and vitamin A-active metabolites has not been investigated. We aim to update what is known about IL-17A, IL-22, and retinoic acid in the pathobiology of liver diseases.

Adaptive Subsets Limit the Anti-Tumoral NK-Cell Activity in Hepatocellular Carcinoma.

Hepatocellular carcinoma (HCC) is a global health burden with increasing incidence, poor prognosis and limited therapeutic options. Natural killer (NK) cells exhibit potent anti-tumoral activity and therefore represent potential targets for immunotherapeutic approaches in HCC treatment. However, the anti-tumoral activity of NK cells in HCC associated with different etiologies, and the impact of the heterogeneous NK cell subset, e.g., adaptive and conventional subsets, are not understood in detail. By comparatively analyzing the NK-cell repertoire in 60 HCC patients, 33 liver cirrhosis patients and 36 healthy donors (HD), we show in this study that the NK-cell repertoire is linked to HCC etiology, with increased frequencies of adaptive NK cells in Hepatitis B virus (HBV)-associated HCC. Adaptive NK cells exhibited limited anti-tumoral activity toward liver cancer cells; however, this was not a result of a specific NK-cell impairment in HCC but rather represented an intrinsic feature, since the characteristics of circulating and intra-tumoral adaptive NK cells were conserved between HD, HCC and liver cirrhosis patients. Hence, the expansion of adaptive NK cells with reduced anti-tumoral activity, detectable in HBV-associated HCC, may have implications for tumor surveillance and therapy.

Serum free light chain is associated with histological activity and cirrhosis in patients with chronic hepatitis B.

BACKGROUND: The antiviral immune response is the main cause of hepatocyte damage and inflammatory necrosis. The serum free light chain, reflecting the immune function of B-cells, is strongly associated with inflammation and disease activity. We aimed to investigate the association of serum free light chain with the progression of chronic hepatitis B. METHODS: A total of 208 eligible chronic hepatitis B patients who had undergone a liver biopsy were studied. Serum free light chains of all patients were measured by turbidimetry using an immunoassay. Liver histology was assessed according to the METAVIR scoring system (which grades the stage of fibrosis on a five-point scale, F0 = no fibrosis to F4 = cirrhosis, and histological activity on a four-point scale, A0 = no activity to A3 = severe activity). The association of serum free light chains with histological activity and fibrosis progression was evaluated. RESULTS: The concentration of serum free light chains in CHB patients increased gradually with histological activity and fibrosis progression. The intensity of histological activity was significantly correlated with the serum free kappa chain (r = 0.658, P < 0.001) and the serum free lambda chain (0.675, P < 0.001). The stages of fibrosis were correlated with the serum free kappa chain (r = 0.683, P < 0.001) and serum free lambda chain (0.664, P < 0.001). After adjusting for age, sex and other synergic factors, the serum free kappa chain remained a potential risk factor, but the serum free lambda chain was no longer associated with liver cirrhosis. Similar to FIB-4 and RPR, the serum free kappa chain exhibited excellent performance in the prediction of liver cirrhosis. The AUCs of serum free Kappa chain, FIB-4 and RPR were 0.873, 0.880 and 0.895, respectively, which were significantly higher than those of the AAR and APRI (0.718 and 0.746). CONCLUSION: Our work revealed that serum free light chains were associated with histological activity and cirrhosis in chronic hepatitis B, which could play a crucial role in the immunopathogenesis of HBV-associated cirrhosis. In addition, free kappa light chain could be a useful predictor of liver cirrhosis.

Cross-tissue single-cell landscape of human monocytes and macrophages in health and disease.

Mononuclear phagocytes (MNPs) encompass dendritic cells, monocytes, and macrophages (MoMac), which exhibit antimicrobial, homeostatic, and immunoregulatory functions. We integrated 178,651 MNPs from 13 tissues across 41 datasets to generate a MNP single-cell RNA compendium (MNP-VERSE), a publicly available tool to map MNPs and define conserved gene signatures of MNP populations. Next, we generated a MoMac-focused compendium that revealed an array of specialized cell subsets widely distributed across multiple tissues. Specific pathological forms were expanded in cancer and inflammation. All neoplastic tissues contained conserved tumor-associated macrophage populations. In particular, we focused on IL4I1+CD274(PD-L1)+IDO1+ macrophages, which accumulated in the tumor periphery in a T cell-dependent manner via interferon-γ (IFN-γ) and CD40/CD40L-induced maturation from IFN-primed monocytes. IL4I1_Macs exhibited immunosuppressive characteristics through tryptophan degradation and promoted the entry of regulatory T cell into tumors. This integrated analysis provides a robust online-available platform for uniform annotation and dissection of specific macrophage functions in healthy and pathological states.